remove old closed bugs and todo items to speed up wiki updates and reduce size

remove old closed bugs and todo items to speed up wiki updates and reduce size

Remove closed bugs and todos that were last edited or commented before 2021.

Except for ones tagged projects/* since projects like datalad want to keep
around records of old deleted bugs longer.

Command line used:

    for f in $(grep -l '|done\]\]' -- ./*.mdwn); do if ! grep -q "projects/" "$f"; then d="$(echo "$f" | sed 's/.mdwn$//')"; if [ -z "$(git log --since=01-01-2021 --pretty=oneline -- "$f")" -a -z "$(git log --since=01-01-2021 --pretty=oneline -- "$d")" ]; then git rm -- "./$f" ; git rm -rf "./$d"; fi; fi; done
    for f in $(grep -l '\[\[done\]\]' -- ./*.mdwn); do if ! grep -q "projects/" "$f"; then d="$(echo "$f" | sed 's/.mdwn$//')"; if [ -z "$(git log --since=01-01-2021 --pretty=oneline -- "$f")" -a -z "$(git log --since=01-01-2021 --pretty=oneline -- "$d")" ]; then git rm -- "./$f" ; git rm -rf "./$d"; fi; fi; done